The method of separation of loose mixture in fluid medium consists in the gravity feed of particles of the material being separated at regular speed, the impact on them with uniform air flow resulted in the output of finished fractions [see Patent of the USSR #1176976 Cl. B 07 B 4/02 issued in the Bulletin #33 on Sep. 7, 1985].
The device for loose material separation contains a fan inlet, feeding bunker located above, and collectors of finished grades with the unit for light particles dropout [see Patent of the USSR #1763051 Cl. B 07 B 4/02 issued in the Bulletin #35 on Sep. 23, 1992].
The effect of air flow to single loose mixture particle is carried out once and only on the random basis in the method and device indicated. Therefore, the quality (accuracy) of the separation is quite low with a rough separation of the mixture into grades. For this reason, such methods and devices are primarily used for pre-treatment of loose mixture from light impurities.
The method of separation of loose mixture in fluid medium consists in the gravity feed of particles, aerodynamic monotonically increasing effect on them at acute angle to the vertical line with the cascade of slot jets resulted in the output of finished grades. This effect is carried out in free alternating power scanning mode with increasing amplitude and scanning angle. The device for separation contains the bunker with vibrating chute, the jet generator installed below, with flat nozzles located one under another at acute angle with the vertical line, the height of cross sections of which, step and installation angle increase top-down. The generator is connected with the source of air supply under pressure and is covered by the side walls. The device has grade collectors located under nozzles [see Patent of Ukraine #45881 Cl. B 07 B 4/02 issued in the Bulletin #4 on Apr. 15, 2002].
Particle separation occurs this way due to the difference ratio of their weight and air resistance force. Due to special mode of air jets effecting loose mixture, this method is more accurate and more stable in time, especially at separating irregular shaped particles. This was possible because the effect with the cascade of jet flow in scanning mode enables to approach each loose mixture particle multiply and in different directions.
But the method and the device have the following drawbacks.
Free alternating jet cascade mode inevitably leads to periodic, unstable in time and space pressure zone origination and discharge with the occurrence of direct and reverse flows. Particles (especially light) are involved in a direction opposite the movement of the main flow, which causes partial mixing with the material already separated. The instability in time of this phenomenon will eventually lead to jet cascade breaking in any random place, which further strengthens the reverse flow in this zone and, consequently, intensifies the process of mixing.
In addition, air jet interruption contributes to the generation breakdown (oscillatory motion cessation) that significantly reduces the quality of separation, bringing it to the quality of separation by usual winnowing machine.
The closest by their essence and the effect achieved are the method and device used to separate loose mixture in fluid medium having been taken for a prototype model, the essence of which is as follows:
The method of separation of loose mixture in fluid medium consists in the gravity feed of particles, aerodynamic monotonically increasing effect on them at acute angle to the vertical line with the cascade of slot jets resulted in the output of finished grades, with the aerodynamic effect carried out in the mode of resonance self-oscillatory motion of each jet and the whole jet cascade on the frequency of fundamental harmonic of fluctuations.
The device for separation of loose mixture in fluid medium contains the bunker with vibrating chute, the jet generator installed below, with flat nozzles located one under another at acute angle with the vertical line, the height of cross sections of which, step and installation angle increase top-down. The generator is connected with the source of air supply under pressure and is covered by the side walls and grade collectors. In this case each pair of contiguous nozzles is equipped with a resonance chamber connected with its inter-nozzle space. Besides, chambers have units equipped for their volume adjustment, where the ratio of the height of the cross section of nozzles to the step of their installation is in the range of 0.2-0.25, and the ratio of the extreme upper and the extreme lower angles of the nozzles installation makes 0.65-0.75 [see Patent of Ukraine #60254 Cl. B 07 B 4/02, A 01 F issued in the Bulletin #7 on Jul. 15, 2005].
Undoubtedly, flat jet cascade application in separation process provides high quality separation of loose mixture into grades, but only if slot jet cascade is in the mode of self-oscillatory motion on the frequency of fundamental harmonic. But self-oscillatory mode requires the device to be equipped with the resonance chambers making the device complicated. In addition, to provide precise resonance frequency, resonance chambers are equipped with their volume adjusting units, and to exclude the possibility of self-oscillatory motion on higher harmonic frequencies, it is required to keep accurately to the step and installation angles of the nozzles. Consequently, despite the fact that the described method of separation of loose mixture in the fluid medium provides the necessary quality of the separation of loose mixture into grades, but its implementation requires a substantial complication of the device and its maintenance difficulties, in particular, the volume adjustment in resonance chambers, which is related to disadvantages. To simplify the same device without rejecting the application of slot jet cascade, cascade formation principle should be changed.
The basis for the invention is creating the method and device for separation of loose mixture in fluid medium providing quality improvement of loose mixture being separated via greater turbulence achievement and device maintenance simplification by forming self-adjusting system by means of optimizing the aerodynamic effect on the particles of initial source material by transferring each jet flow into developed turbulence mode, which totally excludes partial mixing of finally separated material and enhances the quality of separation at multifunctional division of irregularly shaped particles.